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(No Model.) 2 Sheets-Sheet 2. G. R. ELLIOTT.

PNBUMATIG DUUR CHECK. No. 266,795. Patented Oct. 31, 1882.

MMIII.

GILBERT R. ELLIOTT, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE ELLIOTTPNEUMATIC DOOR- CHECK COMPANY, OF4 SAME PLACE.

PNEUMATIC DOOR-CHECK.

SPECIFICATION forming part of Letters Patent No. 266,795, dated October81, 1882.

, Application filed September 5, 1882.

To all whom it may concern Be it known that I, GILBERT R. ELLIOTT, ofBoston, in the county ofSuffolk and State of Massachusetts, haveinvented certain new and useful Improvements in Door-Checks; and I dohereby declare that the following is a full, clear', and exactdescription of the invention, which will enable others skilled in theart to which it appertains to make and use the same, reference being hadto the accompanying drawings, and to the letters of reference markedthereon, which form part of this specification.

This invention relates to that class of inventions known as pneumaticdoor-checks.

The object of the invention is to shut or close a door, and at the sametime prevent the slamming thereof', and also to retain the door in anopen position when desired.

The present invention is an improvement upon an allowed applicationnowin the United States Batent Office, (serial No. 64,329 and itconsists in combining in one cylinder a double cushioning force, wherebythe impelling` force of the spring is neutralized before the doorreaches the contact-point of the sill or jamb, and thereby the slammingof the door is prevented.

It further consistsiu means for retaining the door in an open positionagainst the tension of the spring by the arrangement of the links,levers, and piston-rod in combination with the cylinder.

It further consists in means for retaining the working-cylinder andpiston-rod in a true line, notwithstanding the settling or sagging ofthe door or door-frames or building; and itiinally consists inthecombination, with the cylinder, of a doorcheck and vent-valve of amuliling device, whereby the disagreeable sissing noise, caused by theinduction and eduction of air, is obviated.

For a more complete understanding of my improved door-check, I willrefer to the accompanying drawings, which form a part of thisspeciiication.

Figure lis a perspective view of an ordinary door, partly open, with mydoor-check in position. Fig. 2 is a longitudinal central section (Nomodel.)

on linex x of Fig. 4 through the cylinder, clearly illustrating all theworking parts. Fig. 3 shows a portion of a door, to which is attached adetail of my improvement, and whic'i forms one of the important featuresof my in vent-ion. Fig.4 isa transverse sectional view ofthe cylinder, aface view ofthe piston-head, which shows small apertures around thepiston-rod for the escape of air from one side of the piston-head to theother. Fig. 5 is an end view of the cylinder, showing theair-controlling valve. Fig. 6 represents a top plan View ofthe door anddoor-check, and also the various parts, showing the door open and theposition of the links when closed, the latter being in dotted lines. Theposition now occupied by the door, as shown in this figure, will beautomatically retained when desired to have the door stand open, and theparts will strike t-he segment shown by the dotted lines.

The same letters denote like parts in all the figures.

A is the door, and B the jambs. cylinder; D,thedoor fastening or pivot.E is the piston-rod, and F the connecting-link. G is a link, pivoted toa bracket, a, located on the jamb of the door, and connects toa link,H,by a knuckle or other suitablejoint, b. This link or arm H also connectsto a swivelingsocket, D, on the door, the arm II having` a pintle, c,which lits in said socket D. The socket D is pivoted in the piece I,(see Fig. 3,) which is fastened to the door A and arranged to adjustitself to any angle of the door, either open Or closed or whileswinging. All these parts cooperate with each other, in combination withthe cylinder and mechanism therein, to close the door and prevent itfrom slamming.

Upon one end of the cylinder I locate. what I term a muffler7 J,arranged to move laterally over the valve or valves. This niufiier isperforated on its exterior surface, and also communicates with theinterior of the cylinder by means of a valve, d. This muiiier is filledC is the with sponge or some loose fibrous material, and its object isto break the sissing noise of the escaping air from the cylinder bybreaking its volume into infinitesimal jets, thus destroying itsvelocity, and consequently its noise. Itis obviousthatairpassesintothecylinder through the muffler as well as out. On the other end of thecylinder G is located a stufling-box, f, 5 and having a gland, g,through which the piston-rod works. The spring in the cylinder fits overthe stuffing-box. It is not therefore in the way. The stuffing-box ismade longer than common for the purpose of making it act as a guide forthe piston-romand thus prevent it from shunting.

l will now proceed to describe the internal parts of the cylinder andtheir operation.

K represents the piston head, which is formed ofthe disk-follower L andpacking M. This piston-head (usually rigidly xed) loosely fits thepiston-rod, and hasaround its bore surrounding the piston-rod smallapertures, h, for permitting air to pass through between the rod and the4bore of the piston-head. Upon the face of the piston-head is a disk,t', ot' leather or other flexible material, which forms a valveseat.Rigidly fixed to the piston-rod is another piston-head, N, against whichthe spring works, and ou its opposite side is formed a valve or annularprojection, j, beveled to a knife-edge. This valve-seat j is designed tolit up against the eXible disk i on the piston-head K. ()n the end ofthe piston-rod is an adjusting devicein this instance a piu, Z-which istapering in form; but a set-screw or lock-nut or other equivalent devicemay be used. The piston-head K is adapted to have sliding motion betweenthe piston N and the pin lfor the purpose of allowing the flexible diski on its face to close against the valvej, the object being as follows:When the spring is drawn up the air is expelled from that portion of thecylinder which contains the spring, so that when the door is being shutand the spring expanding with greatforce, a partial vacuum is formedv'in the spring portion ofthe cylinder, and thereby retards the motion ofthe piston in displacing the air from thepiston end ot' the cylinder,and thus assists the air to cushion the door against the rapid action ofthe spring.

Heretofore when the spring has been drawn np the air from the outsidewas drawn in by the piston, which rendered the opening of the door verydifficult, because the air also had to be expelled from behind thepiston through small vents.

With this device, when the spring is drawn up, the' air displaced passesthrough the apertures h, betweenv the bore of the piston-head and itsrod, as well as through the end valve, k. To prevent a perfect vacuum,and entirely prevent the doorfrom closing, I adj ustthe small valve 7cto admit any desired quantity of air that may be found desirable. Theopenings of apertures h of the valve j may be readily adjusted bylessenin g the space between the two piston-heads by driving in thetapering pin, or, it' a nut be used, by screwing it up. This is doneaccording to the size ofthe door and the power ol' resistance. Thevalves d and lo are eccentric in their action, so that thevalve-openings may be regulated and controlled as oceasion may require.

The leverage ot' the apparatus may be varied by changing the pivotalpoints ot' levers F and G.

The apparatus may be secured to the door and door-frame by any approvedmeans; but brackets such as described and shown are preferred. In thepresent instance the cylinder is secured to the door-frame just over thedoor, and the duplex pivotal bracket is secured to the door proper, sothat very little of the apparatus is exposed to view.

Heretofore the cylinder has been placed at right angles to the door, andstood out prominently, which looks very cumbersome and very unsightly.The appearance oi' mine is neat, the parts are simple in construction,readily put together, and effective in operation.v

Having described my invention, and the best means at present known to mefor carrying the same into effect, what I claim as new, and desire tosecure by Letters Patent, is v l. The combination, in a pneumaticdoorcheck,of a cylinder provided with a double piston-head, said headshaving a valve and valveseat, whereby the vacuum on one side of theheads is utilized with the air on the other side of the piston-heads forforming a combined cushioning and holding-back medium, as described.

2. The combination, in pneumatic doorchecks, of a cylinder inclosin goperating mechanism, with a mufiiing device secured thereto to preventthe noise arising either from induc- IOO tion or eduction of the airwhen rapidly entering or escaping from the cylinder, as shown anddescribed.

3. The combination, in a pneumatic doorcheck, ofthe cylinder, doublepiston-heads provided with a valve and valve-seat, as described and theoperating-spring with a muftling device, substantially as described.

4. The combination, in a pneumatic doorcheck, of the cylinder, a piston,a spring, the air-controlling valves, whereby the pressure of air withinthe cylinder-is regulated by its admission and escape, with thenoiseless muffling device, arranged to move laterally over the valve orvalves, and adapted to mu-e the air on its ind uction and eduction,substantially as shown and described.

5. The combination, in a pneumaticdoorcheck,consistingofapistonrod,tight and loose piston-heads or disks,one of said piston-heads having a valve and the other a valve-seat, theloose piston being adapted to approach and recede from the tightpiston-head, and adjustable thereto, whereby, when the piston-heads aremoving in one direction, two forces are made to retard the motion in theopposite direction, the pressure in the cylinder is cqnalized,substantially as set forth.

IIO

6. The combination, in a door-check, of the l In testimony thatclaim theforegoing as my cylinder, the piston-rod E, link F, and links G own I.affix my signature in presence of two and H, the latter having a pintleadapted to l witnesses. revolve in a pivoted socket, said socket alsobeing adapted to adjust itself to any irregulari- Witnesses: ties ofthesettling ofthe door-frame or sagging MINTER P. KEY, of the door,in themanner shown and set forth. B. F. MORSELL.

GILBERT R. ELLIOTT.

